1. Field of the Invention
The present invention relates to a mobile communication system, a mobile communication method, a distribution server, a radio network controller and a mobile station, employing a configuration in which a radio device transmits, to mobile stations, by use of broadcast communication, emergency information transmitted from a distribution server.
2. Description of the Related Art
Heretofore, there have been known mobile communication systems for transmitting emergency information such as earthquake information or “tsunami” information issued by a public office, a local government, or the like.
The emergency information is transmitted to mobile stations by use of broadcast communication such as a cell broadcast service (hereinafter, referred to as a “CBS”) or a multimedia broadcast/multicast service (hereinafter, referred to as an “MBMS”).
Specifically, in such a mobile communication system for transmitting the emergency information, a radio network controller RNC is configured to transmit the aforementioned emergency information to mobile stations located in a particular coverage area, by use of a traffic channel for broadcast communication such as a common traffic channel (CTC) or an MBMS traffic channel (MTCH).
Here, the emergency information is received from a terminal device of a public office, a local government, or the like, via a distribution server.
In such conventional mobile communication systems for transmitting the emergency information, however, the mobile station is not configured to perform authentication of the sender of the emergency information which is by use of broadcast communication.
For this reason, there are problems that credibility of the sender of the emergency information may be lost, and that the receivers may be confused, when the false emergency information is issued by transmission of fake emergency information from an unauthorized radio base station.    (Non-Patent document 1) 3GPP TS23.041    (Non-Patent document 2) 3GPP TS23.246